1. Field of the Invention
The present invention generally relates to the art of making a magnetic recording and/or reproducing head and, more particularly, to a method of making a magnetic recording and/or reproducing head of a type that requires a magnetic head core and a head fixture or support.
2. Description of the Prior Art
The necessity of providing magnetic recording and/or reproducing heads, hereinafter referred to as a magnetic transducer for short, has recently increased because they are one of the major component parts of a magnetic recording and/or reproducing apparatus for recording or reproducing information on or from a magnetic recording medium such as, for example, a length of magnetic recording tape or a magnetic recording disc. Numerous attempts have concomitantly been made to reduce the size of the recording gap defined in the magnetic transducer to improve the recording density. Reduction in gap size often requires an accurate and precise fabrication of the magnetic transducer.
As is well known to those skilled in the art, the magnetic transducer of a type utilized in a magnetic recording and/or reproducing apparatus, for example, a cassette tape recorder, comprises a head core and a head fixture or support on which the head core is fixedly mounted. In fixing the head core in position on the head support, various methods have hitherto been practiced in which the head core is rigidly connected with the head support by the use of a bonding agent, a metal weld or a glass frit, or a combination thereof. Of these methods, the method in which the glass frit is employed is generally considered reliable in that the head core can be rigidly secured in position to the head support.
Hereinafter, the prior art method in which the glass frit is employed for fixing the head core to the head support will be discussed with particular reference to FIG. 4 of the accompanying drawings, which consists of FIGS. 4(a) to 4(d) showing the sequence of making the magnetic transducer.
Referring to FIG. 4, reference numerals 1 and 2 designate the head support and the head core, respectively. In the practice of the method, a heat-resistant fixing jig 3 for retaining the head core 2 in position on the head support 1 and a mold glass or glass frit 4 for fixing the head core 2 to the head support 1 when fused in a heating furnace and subsequently solidified are employed. The method is practiced in the following manner.
The head core 2 is, as shown in FIG. 4(a), first inserted in a slit defined in the head support 1 made of ceramics and is subsequently retained in position in the slit by the use of the heat-resistant fixing jig 3 used to hold the head core 2 immovable relative to the head support 1 as shown in FIG. 4(b). The mold glass or glass frit 4 is then placed on the head support 1 so as to fill up the slit in the head support 1 above the head core 2 as shown in FIG. 4(c). The assembly of FIG. 4(c) including the head support 1, the head core 2, the fixing jig 8 and the glass frit 4 is heated to and retained at an elevated temperature within the heating furnace 5, as shown schematically in FIG. 4(d), to allow the glass frit 4 to be fused. Consequent upon the heating of the glass frit 4 within the heating furnace 5, the glass frit 4 in a fluidized state flows into a gap delimited within the slit between the head support 1 and the head core 2 and, accordingly, when the assembly is subsequently cooled, the glass frit 4 solidifies to connect the head core 2 rigidly to the head support 1.
It has, however been found that the prior art method discussed above has some problems. Specifically, the volume of the heat-resistant fixing jig 3 tends to become a factor of some ten to some hundred times the volume of the head support 1. Also, since the red-hot zone within the heating furnace 5 is limited to a relatively narrow range, a number of assemblies cannot be loaded into the heating furnace 5 at a time and, therefore, a number of heating furnaces are required to accomplish a mass production for a given time.
Also, where the heat-resistant fixing jig is employed, the fixing jig is susceptible to thermal expansion within the heating furnace to such an extent as to result in an undesirable deviation of the head core from the predetermined position relative to the head support.